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authorMiklos Szeredi <mszeredi@redhat.com>2021-11-04 14:04:52 +0100
committerMiklos Szeredi <mszeredi@redhat.com>2021-11-04 14:04:52 +0100
commit5b0a414d06c3ed2097e32ef7944a4abb644b89bd (patch)
tree2f8bb028cbced106482b9be0d53a1e091f8ae054 /fs/overlayfs
parent1f5573cfe7a7056e80a92c7a037a3e69f3a13d1c (diff)
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ovl: fix filattr copy-up failure
This regression can be reproduced with ntfs-3g and overlayfs: mkdir lower upper work overlay dd if=/dev/zero of=ntfs.raw bs=1M count=2 mkntfs -F ntfs.raw mount ntfs.raw lower touch lower/file.txt mount -t overlay -o lowerdir=lower,upperdir=upper,workdir=work - overlay mv overlay/file.txt overlay/file2.txt mv fails and (misleadingly) prints mv: cannot move 'overlay/file.txt' to a subdirectory of itself, 'overlay/file2.txt' The reason is that ovl_copy_fileattr() is triggered due to S_NOATIME being set on all inodes (by fuse) regardless of fileattr. ovl_copy_fileattr() tries to retrieve file attributes from lower file, but that fails because filesystem does not support this ioctl (this should fail with ENOTTY, but ntfs-3g return EINVAL instead). This failure is propagated to origial operation (in this case rename) that triggered the copy-up. The fix is to ignore ENOTTY and EINVAL errors from fileattr_get() in copy up. This also requires turning the internal ENOIOCTLCMD into ENOTTY. As a further measure to prevent unnecessary failures, only try the fileattr_get/set on upper if there are any flags to copy up. Side note: a number of filesystems set S_NOATIME (and sometimes other inode flags) irrespective of fileattr flags. This causes unnecessary calls during copy up, which might lead to a performance issue, especially if latency is high. To fix this, the kernel would need to differentiate between the two cases. E.g. introduce SB_NOATIME_UPDATE, a per-sb variant of S_NOATIME. SB_NOATIME doesn't work, because that's interpreted as "filesystem doesn't store an atime attribute" Reported-and-tested-by: Kevin Locke <kevin@kevinlocke.name> Fixes: 72db82115d2b ("ovl: copy up sync/noatime fileattr flags") Cc: <stable@vger.kernel.org> # v5.15 Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
Diffstat (limited to 'fs/overlayfs')
-rw-r--r--fs/overlayfs/copy_up.c23
-rw-r--r--fs/overlayfs/inode.c5
2 files changed, 22 insertions, 6 deletions
diff --git a/fs/overlayfs/copy_up.c b/fs/overlayfs/copy_up.c
index 4e7d5bfa2949..b193d08a3dc3 100644
--- a/fs/overlayfs/copy_up.c
+++ b/fs/overlayfs/copy_up.c
@@ -140,12 +140,14 @@ static int ovl_copy_fileattr(struct inode *inode, struct path *old,
int err;
err = ovl_real_fileattr_get(old, &oldfa);
- if (err)
- return err;
-
- err = ovl_real_fileattr_get(new, &newfa);
- if (err)
+ if (err) {
+ /* Ntfs-3g returns -EINVAL for "no fileattr support" */
+ if (err == -ENOTTY || err == -EINVAL)
+ return 0;
+ pr_warn("failed to retrieve lower fileattr (%pd2, err=%i)\n",
+ old, err);
return err;
+ }
/*
* We cannot set immutable and append-only flags on upper inode,
@@ -159,6 +161,17 @@ static int ovl_copy_fileattr(struct inode *inode, struct path *old,
return err;
}
+ /* Don't bother copying flags if none are set */
+ if (!(oldfa.flags & OVL_COPY_FS_FLAGS_MASK))
+ return 0;
+
+ err = ovl_real_fileattr_get(new, &newfa);
+ if (err) {
+ pr_warn("failed to retrieve upper fileattr (%pd2, err=%i)\n",
+ new, err);
+ return err;
+ }
+
BUILD_BUG_ON(OVL_COPY_FS_FLAGS_MASK & ~FS_COMMON_FL);
newfa.flags &= ~OVL_COPY_FS_FLAGS_MASK;
newfa.flags |= (oldfa.flags & OVL_COPY_FS_FLAGS_MASK);
diff --git a/fs/overlayfs/inode.c b/fs/overlayfs/inode.c
index 832b17589733..1f36158c7dbe 100644
--- a/fs/overlayfs/inode.c
+++ b/fs/overlayfs/inode.c
@@ -610,7 +610,10 @@ int ovl_real_fileattr_get(struct path *realpath, struct fileattr *fa)
if (err)
return err;
- return vfs_fileattr_get(realpath->dentry, fa);
+ err = vfs_fileattr_get(realpath->dentry, fa);
+ if (err == -ENOIOCTLCMD)
+ err = -ENOTTY;
+ return err;
}
int ovl_fileattr_get(struct dentry *dentry, struct fileattr *fa)